As I understand it, there is no requirement for aircraft below 5700kg MTOM to be fitted with TCAS: Surely at this weight that excludes most private light GA?
http://www.caa.co.uk/docs/7/DAP_TA_C...n_ACASII_2.pdf
We carry TCAS to help identify other aircraft, whether on the same frequency or not but transponding. Despite costing more than some gliders (!) it is by no means infallible. Aircraft not transponding don't appear on TCAS.
Exactly what percentage of GA aircraft are fitted with TCAS?, or is the use of the royal 'we' a little too regal? If TCAS costs soooo much, it would be cheaper to fit another transceiver on a fixed frequency of 130.4, and then you could permanently listen out
